Typically, a suspension system of a vehicle is disposed between a vehicle body and a wheel connecting these two rigid bodies through at least one link. The suspension system is vertically supported by a shock absorbing member such as a spring or a hydraulic shock absorber. The system also typically includes several members to harmonize stiffness and flexibility such that relative motion between the vehicle body and the wheel are mechanically harmonized.
A subframe is also typically included in the front-wheel suspension system. The subframe is generally positioned in a longitudinal direction at a front lower portion of a vehicle body connecting the suspension system to the vehicle body. The subframe has a great influence on integrity of the vehicle body. Therefore, the subframe is required to have an integrity greater than a specific level. The subframe must also rigidly support parts of the suspension system disposed on both sides. Because the front wheels are generally used for steering, a steering gear box assembly is also disposed on the subframe. The subframe and steering gear assembly are typically manufactured as separate units and then assembled together. Each of the subframe and steering gear assemblies are required to have relevant integrities in order for them to perform their own roles. Therefore, the size and load of the subframe and the steering gear box assembly increases.
A projection member is also often provided on an upper side of the subframe. The projection member provides for coupling the steering gear box assembly to the subframe. As a result, the gross load becomes even greater. Furthermore, even more space is occupied under the engine compartment as a coefficient of utilization of space of the engine compartment deteriorates.
Drawbacks of the conventional system include a consumption of excessive working time because the subframe and the steering gear box assemblies are assembled in separate processes. Also, an added number of parts are needed for the assemble, increasing manufacturing costs. Furthermore, the lower structure of the vehicle body becomes compacted.
In order to solve the above problems, the applicant provided a steering gear frame assembly in Korea patent application no. 10-2001-0050609. In this steering gear frame assembly, the steering gear box assembly and the subframe are formed as one unit so the overall structure is simplified. However, the size and load of this steering gear frame assembly has remained high. Furthermore, when the type or size of the suspension system is changed, the subframe must also be changed, therefore, the cost for design and manufacture substantially increases.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.